With the development of smart grid and CBM

it’s important to get the insulation status of capacitive devices and MOA.The on-line testing and live testing are still insufficient in precision and equipment’s reliability

so they aren’t used widely by power companies.In this article

a portable live testing system which based on high-precision synchronize sampling with GPS/BD and wireless is studied to improve the precision and convenience of test.The systems theory is introduced

the technologies which apply hardware of GPS/BD-s PPS to start sampling of Σ-Δ type AD

and coordinate with timing under flow control of software

and improve iteration-orthogonal algorithm

reduces the error of relative dielectric loss test

improves the repeatability and stability of data.The algorithm and synchronize performance are studied with comparison.The system’s performance is tested.The result shows that this system can measure relative dielectric loss with very high precision which-s error less than 0.05%.This system has been used successfully in a substation’s capacitive devices and MOA test

and it improves the test efficiency and cost performance greatly.